Hamlington, Ben

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Old Dominion University

Old Dominion UniversityODU Digital CommonsJuly 29, 2016: The Latest in Sea Level Rise Science Hampton Roads Sea Level Rise/FloodingAdaptation Forum7-29-2016Subsidence Monitoring in Hampton Roads UsingSatellitesBen HamlingtonOld Dominion UniversityFollow this and additional works at: https://digitalcommons.odu.edu/hraforum_13Part of the Geology Commons, Geophysics and Seismology Commons, and the Oceanographyand Atmospheric Sciences and Meteorology CommonsThis Presentation is brought to you for free and open access by the Hampton Roads Sea Level Rise/Flooding Adaptation Forum at ODU DigitalCommons. It has been accepted for inclusion in July 29, 2016: The Latest in Sea Level Rise Science by an authorized administrator of ODU DigitalCommons. For more information, please contact digitalcommons@odu.edu.Repository CitationHamlington, Ben, "Subsidence Monitoring in Hampton Roads Using Satellites" (2016). July 29, 2016: The Latest in Sea Level RiseScience. 8.https://digitalcommons.odu.edu/hraforum_13/8Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Subsidence	Monitoring	in	Hampton	Roads	Using	Satellites	!Ben Hamlington!Center for Coastal Physical Oceanography!Ocean, Earth and Atmospheric Sciences Department!Old Dominion University!!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Collaborators!•  Brett Buzzanga |   Old Dominion University!•  David Bekaert |   NASA JPL!•  Cathleen Jones |   NASA JPL!•  John Murray |   NASA Langley!•  Jack Eggleston |   USGS!•  Michelle Sneed |   USGS!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Sea Level Rise in Hampton Roads!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Sea Level Rise in Hampton Roads!•  How much of the trend is the ocean rising, and how much of the trend is the land sinking?!–  50% ocean rising, 50% subsidence (?).!•  Three main (known) causes of the subsidence:!–  Glacial Isostatic Adjustment (Post-glacial rebound)!–  Chesapeake Bay Impact Crater!–  Groundwater Removal!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Glacial Isostatic Adjustment (GIA)!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Glacial Isostatic Adjustment (GIA)!•  Vertical land motion (mm/year) associated with GIA.!•  Positive values indicate uplift, while negative values indicate subsidence. !Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Chesapeake Bay Impact Crater!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Groundwater Removal!•  This map shows estimates from subsidence for the time period from 1940 to 1971. !•  High subsidence rates are centered near paper mills in West Point and Franklin.!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Hampton Roads Subsidence!•  This map shows estimates from subsidence for the time period from 1940 to 1971. !•  What does the subsidence map look like now? !•  Is there greater (finer-scale) spatial variability than indicated by this map? !•  To answer these questions, we can use Interferometric Synthetic Aperture Radar (InSAR) analysis.!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 What is SAR/InSAR?!•  A synthetic aperture radar (SAR) is a side-looking (active) remote sensing system which utilizes the flight path of the platform (plane or satellite) to simulate a large antenna à higher resolution imagery. !•  InSAR analysis compares two (or more) SAR images of the same area, taken by the same satellite at the same vantage point, but at different times to estimate surface deformation or elevation.!–  Relies on differences in the phase of the waves returning to the satellite, which can then be converted into displacement. !Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 What do we need to measure the rate of subsidence?!•  To get accurate satellite-derived measurements of long-term subsidence in the region, we need:!–  A long record!–  Good sampling within that record (lots of data points)!–  Consistent overflights of the satellite!–  In situ measurements for calibration and ground-truthing/validation!–  Ability to correct for sources of error!•  Anything that causes a delay in the time it takes for the signal to propagate from the target to the satellite will result in error that (ideally) needs to be accounted for.!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Preliminary InSAR Analysis!•  As a starting point, we have performed a preliminary InSAR analysis for the region.!–  Goal: Analyze historical SAR data with a simple processing tool to compute an initial subsidence rate map.!–  Here, we are using the GMTSAR software. !•  Steps:!1.  Find any SAR data coincident with Hampton Roads region.!2.  Assess the quality of this data.!3.  Estimate a subsidence map using simple InSAR analysis.!!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Available Data!•  For historical SAR data, ERS and ALOS-1 appear to provide the best coverage of HR with the longest available time series.!•  Initial analysis will use data from ALOS-1 PALSAR (Japanese satellite).!–  Data is (publicly) available over HR from 2006 through 2011. !–  Some of the available frames are shown in figure on the right, with each frame measured along multiple passes of the satellite. !Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Available Data!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Available Data!•  Satellite baseline for ALOS-1 Frame 730 (12 images available from 2006 to 2011). Critical baseline ~1000 m. !2006 2007 2008 2009 2010 2011 2012 Year-2000-100001000200030004000 Baseline (m)48441289614238189352229022961236322430324974256452631626987Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Available Data!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Subsidence Map!•  Skipping a lot of steps….subsidence rates (mm/yr) from December 22nd, 2006 to January, 14th, 2011.!!!•  After removing the long wavelength signals (e.g. GIA), we are left with what can be interpreted as an “anomaly” displacement map.!•  This can provide information regarding what areas subsided more over this time period than others. !•  It does not, however, provide information regarding absolute displacement, as the longest wavelength signals like GIA are removed à further work is needed.!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Problems!–  A long record!–  Good sampling within that record (several data points)!–  Consistent over-flights of the satellite!–  In situ measurements for calibration and ground-truthing/validation!–  Ability to correct for sources of error!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Problems!–  A long record!–  Good sampling within that record (several data points)!–  Consistent over-flights of the satellite!–  In situ measurements for calibration and ground-truthing/validation!–  Ability to correct for sources of error!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 ODU/CCRFR/NASA Collaborative Subsidence Project!•  To improve on this preliminary subsidence map, ODU, CCRFR, and NASA have formed a collaborative project designed to get the “most” out of the available data.!–  Funding will be provided jointly by the CCRFR and a NASA Rapid Response proposal. !–  InSAR experts, David Bekaert and Cathleen Jones from NASA JPL, will work with scientists at ODU to both perform state-of-the-art analysis of the available SAR data and build capacity at ODU to perform this analysis in the future. !–  John Murray (NASA Langley) will coordinate the effort between NASA JPL and ODU. !–  Will use ISCE, TRAIN, and StaMPS/MTI software to perform the analysis, with dramatically improved atmospheric correction procedures.!!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Persistent Scatterer InSAR Analysis!•  We will use the Persistent Scatterer InSAR (PSInSAR) method to obtain higher resolution and more accurate subsidence rate maps.!•  PSInSAR relies on features within the field of view that provide permanent “scattering points”. !–  Features such as roof tops, bridges, dams, antennae, large rock outcrops, etc. make good persistent scatterers.!–  Using the technique (and without getting into details), the motion of each scatterer structure can be very precisely tracked and vertical land motion can be determined.!–  Technique performs better in urban areas than rural. !Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Persistent Scatterer InSAR Analysis!Dixon,	Timothy	H.,	Falk	Amelung,	Alessandro	FerreA,	Fabrizio	Novali,	Fabio	Rocca,	Roy	Dokka,	Giovanni	Sella,	Sang-Wan	Kim,	Shimon	Wdowinski,	and	Dean	Whitman.	2006.	“Space	Geodesy:	Subsidence	and	Flooding	in	New	Orleans.”	Nature	441	(7093):	587–88.	Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Persistent Scatterer InSAR Analysis!Dixon,	Timothy	H.,	Falk	Amelung,	Alessandro	FerreA,	Fabrizio	Novali,	Fabio	Rocca,	Roy	Dokka,	Giovanni	Sella,	Sang-Wan	Kim,	Shimon	Wdowinski,	and	Dean	Whitman.	2006.	“Space	Geodesy:	Subsidence	and	Flooding	in	New	Orleans.”	Nature	441	(7093):	587–88.	Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Summary!•  By the end of the year, we will have a preliminary subsidence map for a portion of Hampton Roads (frames 720 and 730) using PSInSAR analysis that will be made publicly available.!–  By mid-2017, we will expand our analysis to the entire Hampton Roads region, releasing final subsidence maps.!–  There is a limit imposed by the data on how well we can do with what is currently available.!–  Our initial goal is to extract the best possible information regarding recent subsidence rates in Hampton Roads.!–  By the end of the project, ODU will have the capacity to perform state-of-the-art InSAR analysis. !•  The work completed here will help inform how subsidence can be monitored in Hampton Roads using satellites.!–  With the coverage of SAR satellites increasing, this is a vital step towards determining how best to perform ongoing and continuous subsidence monitoring in the region.!Old Dominion University Center for Coastal Physical Oceanography July 29th, 2016 Thanks for your time!!

Subsidence Monitoring in Hampton Roads Using Satellites

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Subsidence Monitoring in Hampton Roads Using Satellites

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